Search

The synthesis and crystal structure of octanuclear zinc(II) and cobalt(II) clusters that could be obtained by the cooperative tetrameric assembling of the 3-hydroxy-salamo ligand is reported. The structural analysis of the zinc(II) complex in solution has displayed the significant stability of the octanuclear core, suggesting that the tetrameric self-assembly took place highly cooperatively.

The synthesis of novel zinc(II) complexes [Zn3L2(OAc)2] and their structures were determined by x-ray crystallography. The complexes between the salamo ligands and zinc (II) in methanol formed exclusively and very cooperatively.

A new type of acyclic bis([N.sub.2][O.sub.2] chelate) ligand has afforded a C-shaped [O.sub.6] site by the metalation of the [N.sub.2][O.sub.2] salamo sites. The different nature of the [N.sub.2][O.sub.2] and [O.sub.6] sites of the ligand [H.sub.4]L has led to the site-selective introduction of two different d-block transition metals.

The new salen-type [N.sub.2][S.sub.2] tetradentate ligands having a donor set comprising oxime and thiol groups and the unsymmetrical [N.sub.2]SO ligands are synthesized. Mononuclear complexes are obtained by complexation of the ligands with palladium(II) acetate without N-O bond cleavage.

The article explains the highly cis- and trans-selective synthesis of a 32-membered macrocyclic tetraoxime. The synthesis is shown to be a ring-closing olefin metathesis reaction exhibiting the oligometallic template strategy.

A 36-membered macrocyclic hexaoxime is obtained by [3+3] condensation of dialdehyde with diamine by using [La.sup.3+] and [Zn.sup.3] as a novel core/shell template. The high yield is attributed to the formation of a 3:3:1 complex of dialdehyde, which has readily given the macrocycle keeping the [Zn.sub.3]La core/shell tetranuclear cluster structure.

A new discrete heterotrinuclear complex [LCu2Gd(OAc)(sub 3)] is synthesized from a linear tetraoxime ligand. The corresponding dinuclear CuGd complexes, with mono(salen)-type chelate 3-MeOsalamo are also synthesized.

Synthesis and binding behavior of a novel multi-responsive host, in which two esters, two polyether moieties, two urea sites, and two bipyridine units as ion binding sites are arranged on the calix-[4]arene skeleton, is described. This host recognizes Na(super +) and Ag(super +) simultaneously and quantitatively and captures an anionic guest.

The first isolation of a salen-type chelate ligand containing a thiosalicylidene moiety and the synthesis of the nickel(II) complex is reported. A new oxime-type N2S2 ligand, H2tsalamo, which is much more stable than the imine analogue, H2tsalen, is synthesized and isolated.

A series of new ligands salamo (=1,2-bis(salicylideneaminooxy)ethane) on the basis of O-alkyl oxime instead of the imine moiety is synthesized, to develop stable analogues of salen-type ligands. The ligands are prepared by the reaction of 1,2-bis(aminooxy)ethane with two equivalents of salicyladehyde derivatives under mild conditions.

A novel ion recognition system based on multinuclear zinc (II) complexes that utilize the selective exchange of metal ions is reported. To utilize it as a novel ion sensor, the addition of fluorophores at the end of the linear ligand is investigated.

A novel allosteric host pseudocryptand using Fe(II) as an effector to control the positive and negative allosteric effects is proposed. The results indicate that an external stimulus can control the kinetic ion-recognition process.